Necromancers can posses body's with dead spirits. Spirit possession is a term for the belief that animals, demons, extraterrestrials, gods, or spirits can take control of a human body. The concept of spirit possession exists in many religions, including Christianity, Buddhism,Haitian Voodoo, Wicca, Hinduism, Islam and Southeast Asian and African traditions. Depending on the cultural context in which it is found, possession may be considered voluntary or involuntary and may be considered to have beneficial or detrimental effects to host. Within possession cults, the belief that one is possessed by spirits is more common among women than men.

Demonic possession is held by many belief systems to be the spirit possession of an individual by a malevolent preternatural being, commonly known as a demon. Descriptions of demonic possessions often include erased memories or personalities,convulsions, “fits” and fainting as if one were dying. Other descriptions include access to hidden knowledge (gnosis) and foreign languages (xenoglossia), drastic changes in vocal intonation and facial structure, the sudden appearance of injuries (scratches, bite marks) or lesions, and superhuman strength. Unlike in channeling, the subject has no control over the possessing entity and so it will persist until forced to leave the victim, usually through a form of exorcism.

Many cultures and religions contain some concept of demonic possession, but the details vary considerably. The oldest references to demonic possession are from the Sumerians, who believed that all diseases of the body and mind were caused by "sickness demons" called gidim or gid-dim. The priests who practised exorcisms in these nations were called ashipu (sorcerer) as opposed to an asu (physician) who applied bandages and salves. Many cuneiform clay tablets contain prayers to certain gods asking for protection from demons, while others ask the gods to expel the demons that have invaded their bodies.

Shamanic cultures also believe in demon possession and shamans perform exorcisms. In these cultures, diseases are often attributed to the presence of a vengeful spirit(or loosely termed demon) in the body of the patient. These spirits are more often the spectres of animals or people wronged by the bearer, the exorcism rites usually consisting of respectful offerings or sacrificial offerings.

Christianity holds that possession derives from the Devil, Satan, or one of his lesser demons. In many Christian belief systems, Satan and his demons are actually fallen angels.

Body hopping is the fictional ability and desire to possess people in quick succession. A body hopper can transfer quickly from one physical body to another physical body with little or no resistance and few conditions on moving on to a new body, and usually without getting stuck in said body for a long period of time.